我对如何实现PlaybackParams有疑问设置视频速度:publicPlaybackParamsgetPlaybackParams()AddedinAPIlevel23GetstheplaybackrateusingPlaybackParams.PlaybackParamssetSpeed(floatspeed)//Setsthespeedfactor.Returns:theplaybackratebeingused.ThrowsIllegalStateException:iftheinternalsyncengineortheaudiotrackhasnotbeeninitial